1. Field of the Invention
The present invention generally relates to bipolar endoscopic instruments and, more particularly, to bipolar forceps or tongs.
2. Description of Related Art
A bipolar instrument may be bipolar forceps or tongs of which the arms or jaws make contact with the two terminals of a high-frequency (hf) source. Illustratively bipolar forceps are used to seize and coagulate tissue. However, they also may be bipolar scissors cutting and simultaneously coagulating the cut tissue surfaces.
In general, power is applied from the two output terminals of the hf source, through the proximal instrument end, to the jaws. As regards the above cited bipolar endoscopic instruments, the two output terminals are insulated from each other and, by means of a two-contact hf plug, are connected to the inside of the instrument. The end of the hf plug inserted into the instrument is configured such that the two plug contacts are axially shifted from each other, each making contact inside the instrument with a contact element electrically connected to a particular jaw. In general, the hf plug is configured at an acute angle to the thrust and/or pull element or wire, hereafter push/pull wire, and to the proximal instrument end.
The application of output power from the two terminals of the hf source through the two-contact hf plug to the inside of the instrument raises problems. Because of the relative compactness inside the instrument, considerable effort must be devoted to conduct the power from the two hf source terminals through a two-contact hf plug into the instrument inside and to guide this power within the instrument to the distal jaws.
Accordingly, it is the objective of the present invention to simplify the transition from the hf plug into the inside of a bipolar endoscopic instrument of the above kind.
Inside the instrument of the invention, there is a unit comprising two contact elements configured in axially consecutive manner and electrically insulated from each other by an electric insulator.
The angle and the site of insertion of the hf plug are selected such that the plug, by its applied end, engages the insulator. The applied plug end is configured such that each time one hf source terminal makes contact with one contact element of the unit.
By using the above unit, the two hf source terminals may be connected in a very simple manner through a two-contact hf plug into the inside of the bipolar endoscopic instrument and from there with the contact elements.
In further accordance with the present invention, the two contact elements are cylindrical and are configured longitudinally consecutively on a push/pull element or wire. The insulator is disk-shaped and is configured axially between the two contact elements. Electric connection between the contact elements can be effectively prevented by axially mounting the insulator between them.
In further accordance with the present invention, an insulator electrically separates the two contact elements. Therein the contact elements are tubular and can be configured axially into one another. Again, a bush-like insulator is inserted between the two contact elements in order to preclude electric conduction between them.
The manufacture of the contact elements and of the insulator, furthermore the installation of said unit in the instrument, are simple and easily carried out and therefore also economical.
Advantageously, one contact element of the unit is designed to make contact with the push/pull wire, which in turn also is connected in electrically conducting manner with one jaw. The unit""s second contact element is designed such that it contacts the instrument""s stem, which in turn is electrically connected to the other jaw. In this manner electrical conduction can be established between the contact elements and the jaws without resort to additional components.
As already mentioned above, the hf plug is inserted at an acute angle to the push/pull wire in order to improve instrument handling. In order to simplify as much as possible the engagement of the hf plug in the insulator and, simultaneously, the contact between plug contacts and contact elements, the unit is fitted at the level of the insulator with a borehole pointing in the direction of the installation angle of the hf plug.
The borehole preferably shall be threaded to receive the hf plug, which in turn is threaded at its installed end. However, the borehole also may be a socket for the plug.
In order to attain electrical connection between plug contacts and contact elements when the hf plug is inserted into the threaded borehole or the socket, the two projecting plug contacts exhibit symmetry of rotation. As a result the insertion of the hf plug into the instrument does not require a precise plug-in position because electrical connection is attained at any plug-in position.
The unit may be in the form of a prefabricated component made up of individual elements. Illustratively, the insulator may be soldered to the two contact elements. However, the individual constituents also may be separate and be separately inserted into the instrument.